1. Field of the Invention
The present invention relates to an apparatus for the distribution of a fluid and, more specifically, to an apparatus for providing distribution of a fluid from two or more sources.
2. Description of the Related Art
A number of different methods and techniques are available for the disinfection of water. These methods include, for example, filtration, heating, treatment with UV radiation, and treatment with a variety of chemicals, often oxidizers such as chlorine, chloramine and ozone. One of the most widely used treatments for both potable and waste water is to dissolve chlorine in the water. Chlorine may be in a variety of forms, such as, for example, a gas (Cl2), a liquid (sodium hypochlorite solution) or a solid (calcium hypochlorite). Because it is effective, inexpensive and readily available, chlorine gas, which may be compressed to a liquid, is a widely used oxidant in the water treatment industry.
Chlorine gas is typically manufactured off site and is delivered to a water treatment facility in pressurized containers, such as gas cylinders. At the site, for example, a municipal water treatment facility, the chlorine is introduced into the water in a concentration adequate to provide an acceptable level of disinfection. Often, the gas is introduced into the water via a vacuum injector system or a vacuum induction system that draws the chlorine into the water at a pressure that is below atmospheric pressure. When such a technique is used, chlorine is less apt to escape from the disinfection system because, if a leak forms in the system, the constant draw of the vacuum source will prevent the escape of gas to the atmosphere. However, for efficient storage and transportation, chlorine is generally shipped and stored in pressurized containers, and the pressure of the gas must first be reduced to feed a vacuum injector. Such a system is disclosed, for example, in U.S. Pat. No. 6,105,598, which is hereby incorporated by reference in its entirety herein.
Often, a series of pressurized gas cylinders are drawn from in parallel to provide an adequate supply of gas. Multiple cylinders may be plumbed to a single vacuum regulator, so that the gas is at greater than atmospheric pressure upstream of the regulator and below atmospheric pressure downstream. A vacuum regulator, such as the S10K™ vacuum regulator, available from United States Filter Corporation, Vineland, N.J., may be used to provide a low pressure source of chlorine, or other gases, to a vacuum injector system from a number of gas sources, such as chlorine cylinders or tanks. When a pressurized gas, for example, chlorine gas, is fed to a regulator from multiple tanks, the tanks may be emptied without significant drops in temperature as there is minimal gas expansion upstream of the regulator.
Many users of vacuum injection systems, particularly those disinfecting a water supply, may prefer to use a bank of cylinders where each gas cylinder is independently regulated. In this case, each cylinder may be fitted with a vacuum regulator that is then used to feed a common, low-pressure gas manifold. Such a configuration may reduce the total amount of high pressure gas piping that is required at a facility. However, this configuration may also mean that high pressure gas is being reduced to low pressure gas at numerous locations, such as at the point of exit of each of the gas cylinders. If there are slight differences in regulator design or construction, or if each cylinder is not identically situated, gas may be drawn preferentially from one cylinder rather than equally from all, resulting in unequal gas distribution from containers within a bank or between banks. In this instance, significant gas expansion and/or boiling may occur in a tank being drawn down at an excessive rate, which may result in a variety of problems, including frosting, that may interfere with the function and output from one or more cylinders. This unequal and unpredictable cylinder depletion may result in a failure to maintain a consistent supply of gas to the low pressure system.